Method and apparatus for electrical dehydration



May 23, 1936- P. W. vPRxJ-rzwluu 2,041,954

METHOD AND APPARATUS FOR ELECTRICAL DEHYDRATION Filed Oct. 10, 1953Patented May 26, 1936 UNITED STATES METHOD AND APPARATUS FOR ELEC-TRICAL DEHYDRATION Paul W. Prutzman, Los Angeles, Calif., assignor toSocony-Vacuum Corporation, New York, N. Y., a corporation of New YorkApplication October 10, 1933, Serial No. 692,977

Claims.

The object of my invention is to provide means and a method forsimultaneously resolving and separating the phases of an emulsion of thewater-in-oil type, and more specifically a pe- 5 troleum emulsion.

The method of resolving emulsions which consists in subjecting them tothe action of a high tension electrical field was disclosed by Cottrelland others as early as 1911 (see U. S. Patent 987.

D 115), is very Well known and understood and needs but the briefestdescription.

'In general terms, the emulsion is passed between opposite chargedelectrodes on which a high potential is impressed. This potential pro- 5duces a static electrical field between the electrodes and, under theinfluence of this field, electrical charges are imparted to thesuspended water particles. These charges cause the particles to approacheach other and to. coale'sce to I larger particles and droplets whichiinally attain such dimensions as to settle out of the oil.

This is purely a static eiect and ceases if any material leakage orconduction between the electrodes occurs. The tendency of the liberatedwater particles is to arrange themselves along the lines o force at suchminute intervals as to form conductive chains by breaking down thedielectric oil layer between them. When this occurs, the static eld isdissipated by conduction and the resolving effect ceases until the eldis reestablished.

In order to maintain the integrity of the field and the continuedfunctioning of its resolving effect, it is necessary to maintain adielectric barrier between the electrodes at all times. To this endseveral methods have been proposed. Cottrell (Patent 987,115) dilutesthe emulsied oil with relatively dry oil, by which step the distancebetween the water particles and the thickness of the dielectric oilbarrier between them is increased. Fisher (Patent 1,838,928) interposesa barrier layer of relatively dry oil between one of the electrodes anda layer or stream o f emulsion which is in contact with the oppositeelectrode. Peek (Patent 1,170,184) interposes a solid dielectric barriersuch as glass between one of the electrodes and a layer of emulsionwhich is in contact with the opposite electrode. McKibben (Patent1,276,386) sweeps the water particles out of the eld as fast as they areformed, thus maintaining in the field a constantly renewed supply ofemulsion which, prior to resolution, has usually a high dielectricvalue.

The method of the instant application adopts the latter alternative andis directed to a. specinc (ci. zoll-24) method and means for passing aconstantly renewed supply of emulsion through a succession of high4intensity fields into interposed zones of quiescence from which freewater is drained to a point outside the apparatus.

The objects and advantages of the inventionmay best Vbe understood withreference to the attacheddrawing, which represents in vertical sectionand internal elevation a preferred form of apparatus which may be usedto illustrate the m method employed.

Referring to the drawing, I0 is a substantially closed shell which maybe of any preferred dimensions. 'I'his shell is divided into a pluralityof compartments IIa, IIb, etc. by partition members which may consist,as shown at .the right side of the drawing, of a ring I2 tightlyattached to the shell, a truncated cone I3 attached to the ring, and arelatively short nozzle I4 attached to the upper end of the cone.Alternatively the opening through the plate may be of the same diameteras the nozzle, which may then be of greater length and attached directlyto the ring without the use of the cone, as shown in dotted lines at 31.25

The upper end of each nozzle is faced olf square and opposed to thisfaced end is a cup shaped member I5, having its downwardly projectingrim aligned with the upper rinl of the nozzle and spaced therefrom toleave a circumferential "slot 2Ia, 2lb, etc. These cups are firmlyattached to a stili rod or tube IE, which will be closed at the lowerend as at Il if a tube is used.

The rod or tube I6 passes through an insulator I8 ixed4 in the upperhead of the shell and may 35 be threaded as at I9 and provided with ahand nut 20 for raising and lowering. If the rod is made movable in thismanner, it should be passed through a stuiling box not shown.

A cable 22 connects an end of rod I6 with one 40 terminal of thesecondary winding of al step-up transformer 23, the other secondaryterminal being grounded as at 2B. The primary winding has its terminalsconnected to a source of supply of alternating current. The shell itselfshould be grounded, as indicated at 36'.

AWhen connected in this manner, the upper ri of nozzle |42 is theeifective part of the grounded electrode, being conductively attached tothe shell, while the cup I5 functionsas the live electrode. 50

An emulsion supply pipe 25 communicates with the lower compartment IIaat an intermediate point in its height. An outlet pipe 26 is attached tothe upper head of the shell, this pipe branching as atzl to act as avent for aas or u n vapor which may be released within the apparatus andat 28 to conduct away treated oil. A water drain pipe 30 branches at29-29 to each compartment, each of these branches being optionallycontrolled by a manual valve 3l or a float actuated valve 32 adapted tomaintain a substantially constant water level 33 inthe compartment, thelatter being preferred. A sight glass indicated at 34 or a succession oftry-cocks 35 may be used to indicate the momentary water level, thesebeing particularly useful for manual control.

It is essential that the rims of cups I5 and nozzles I4 be maintained insubstantial alignment and4 if the length of the insulator I8 and thebearing of the rod I6 therein do not suiice for this purpose, a lowerinsulator 38 supported as by a cross-bar 39 may be used. This insulatorshould be recessed as at 40 to permit vertical.

'it enters the apparatus.

The settled emulsion moves slowly upward .in the lower compartment andpasses through the slot 2Ia, into the next higher compartment I Ib. Adesired electrical potential, as of the order of 5,000 to 12,000 volts,being impressed on the electrodes, a highly concentrated field isestablished in the slot or gap 2l a, the width of this gap and, byconsequence, the intensity of the field, being variable by raising orlowering rod I6.

In passing through this field the em ion is partially resolved into itsconstituents in t e well known manner, and such velocity is maintainedthrough the gap as to sweep away the liberated water particles as fastas they are formed, thus preventing the formation of conductive waterchains and the dissipation of the field.

'Ihe resolution products, consisting of oil'containing unbroken emulsionand suspended drops of free water, emerge from gap 2Ia into compartmentIll, where their velocity'is so retarded 'that the free water has ampleopportunity to settle from the oil and join the water layer Vin thebottom of the compartment, from which it is withdrawn. The oil thusfreed from water moves upwardly through the compartment, to and throughthe next field, and the above operations are repeated as many times asthere are ields, the rate of ow being soadjusted that after passingthrough the last iield the emulsion 'will have been completely resolved,the nal compartment IId receiving only completely treated oil and aresidual quantity of suspended water.

.This water having /been removed in the nal compartment, only treatedoilis delivered to out- I let pipe 28.

fleld gaps 2| in the direction of oil iiow. This provision is made inthe original spacing of the live electrodes I5 on`the electrode rod I6.In thus decreasing the width of the gap the field is correspondinglyintensified so that the most stub- 5 born residual traces of emulsionmay be completely resolved.

'Ihe structure shown is adapted to the treatment of any emulsion inwhich water is the dispersed phase, no matter how refractory, and will10 produce a complete resolution of the emulsion and iinal separationofthe phases in a single pass through the treater.

The apparatus show'n has important advantages over other dehydratingapparatus hereto- 15 fore disclosed. As the electrodes are of relativelythin sheet metal (a thickness of one-eighth inch is ample), the field ishighly concentrated at the opposed edges. As these edges are identicalin circumferential length, each individual 20 field has the sameintensity adjacent each edge. The relative intensities of the successivefields may be varied at will, and the intensities of all the fields maybe simultaneously varied to suit different classes of emulsion. Theprovision of 25 retardation chambers and of means for removing Waterfrom each, together with .the positive direction of the emulsion throughthe successive fields, permits the maintenance of fields of extremelyhigh intensity and effectiveness.

I claimas my invention:

1. An electrical dehydrator comprising: a vertically arranged andsubstantially closed shell; a grounded electrode inthe form of ahorizontal partition conductively attached to said shell and 35,'

a nozzle projected upwardly around an opening through said partition,said nozzle and said partition dividing said shell into chambers andcooperating with the wall of said shell to form' a receptacle for water;a live electrode in the form i0` in spaced relation to the upper edge ofsaid 45g nozzle; means for introducing emulsion into the chamber belowsaid electrodes and for forcing said emulsion between lsaid electrodesinto the chamber above said electrodes; means for withdrawing oil andgas from said upper chamber; 50 means for withdrawing water from thelower portion of said lower chamber; means independent of last saidmeans for withdrawing water from the receptacle formed by said groundedelectrode, and means for impressing an electrical potential 55 on saidelectrodes.

2. Apparatus substantially as and for the purpose set forth in claim 1,including means for controlling the space relation between said cup andsaid nozzle. 6(

3. Apparatus substantially as and for the purf pose set forth in claim1, including a plurality of said partitions, nozzles and cups dividingsaid shell into chambers and forming a plurality of receptacles forwater, the sole communication be- 6, tween adjacent of said receptaclesbeing the annular space between said electrodes.

4. Apparatus substantially as and for the purpose set forth in claim 1,including a plurality of 1 said partitions, nozzles and cups, said cupsbeing 7 so arranged on 'said supporting means that the space relation.between each cup and its corresponding nozzle is greater than the spacerelation between the cup and nozzle next thereabove.

5. Apparatus substantially as and for the purpose set forth in claim 1,including a plurality of said partitions, nozzles and cups, said cupsbeing so arranged on said supporting means that the space relationbetween each cup and its corresponding nozzle is greater than the spacerela-

